JP2007228049A - Imaging apparatus control unit and digital camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging device control unit and a digital camera the power consumption of which is reduced. <P>SOLUTION: The digital camera has a photographing mode. The digital camera displays a through-image on a liquid crystal monitor in the photographing mode. An AFE transmits an imaging device drive signal corresponding to a high frequency frame signal to an imaging device when the photographing mode is started (step S100). The imaging device receiving the imaging device drive signal corresponding to the high frequency frame signal images an object image by each 1/30 sec. The imaging device generates an image signal equivalent to the object image. When the photographing mode is started, a DSP makes a timer start clocking of time. When the time clocked by the timer elapses a prescribed time (step S105), the AFE transmits the imaging device drive signal corresponding to a low frequency frame signal to the imaging device (step S107). The imaging element receiving the imaging device drive signal corresponding to the low frequency frame signal images the object image by each 1/15 sec. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus control unit and a digital camera that control operations set in an imaging apparatus such as a digital camera.

  In a digital camera, electronic data corresponding to an image captured by imaging a subject is generated and stored. Electric power is consumed for generating and storing electronic data. In addition, the digital camera is provided with predetermined functions, and power is consumed to execute some of these functions.

  Power used for operation of these digital cameras when they are carried is supplied by a rechargeable battery. The electrical energy that can be stored in the rechargeable battery is finite. Therefore, when the electric energy of the rechargeable battery is used up, various functions including imaging of the subject cannot be executed.

  Accordingly, it is an object of the present invention to provide an imaging device control unit and a digital camera that reduce power consumption.

  An imaging apparatus control unit according to the present invention is an imaging apparatus control unit that controls a predetermined operation set in an imaging apparatus having an imaging element that images a subject, and that receives a command input that causes the imaging apparatus to execute a predetermined function. A receiving unit that receives a predetermined input operation commanded to the operation input unit to be performed as an operation signal, a timer that starts measuring time when the receiving unit receives the operation signal, and a time that the timer measures is first Before the time elapses, the subject is imaged at the first interval by the image sensor, and after the first time is measured by the timer, the subject is captured at the second interval longer than the first interval by the image sensor. An image sensor driving unit for imaging is provided.

  Furthermore, the elapsed time is preferably reset when a new operation signal is received by the receiving unit.

  The image sensor driving unit includes a frame signal generator that generates a frame signal that defines the number of times the subject is imaged per unit time in the image sensor, and a frame signal before the time measured by the timer passes the first time. A cycle in which the generation unit generates a frame signal having a first interval and causes the frame signal generation unit to generate a frame signal having a second interval after the time measured by the timer has passed the first time. It is preferable to have an adjustment unit.

  In addition, it is preferable that the timer starts measuring time even when the power of the imaging apparatus is turned on.

  In addition, the image corresponding to the optical image of the subject imaged by the image sensor is displayed so that the image is displayed darker than the time before the first time after the time when the timer measures the first time. It is preferable to provide a monitor control unit for controlling the monitor.

  In addition, it is preferable that the image sensor driving unit causes the image sensor to continue imaging at the first interval by inputting a switching stop command to the operation input unit.

  In addition, when the switching stop command is input to the operation input unit, the image sensor driving unit causes the image sensor to continue imaging at the first interval, and the monitor control unit maintains the average luminance of the entire monitor as the first luminance. It is preferable to drive the monitor.

  The digital camera of the present invention starts measuring time when a predetermined input operation is performed on an operation input unit that performs an image input for imaging a subject, a command input for executing a predetermined function, and a command input. The timer, and before the time measured by the timer passes the first time, the subject is imaged at the first interval, and after the time measured by the timer passes the first time, the subject is placed on the image sensor. An image sensor drive unit that captures images at a second interval longer than the first interval is provided.

  According to the present invention, if there is no operation input to the digital camera, the interval at which the imaging device captures the subject image is lengthened, so that power consumption in the digital camera can be reduced. Further, if there is no operation input, the image displayed on the monitor is darkened, so that power consumption can be further reduced.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram schematically showing an internal configuration of a digital camera having an imaging apparatus control unit to which an embodiment of the present invention is applied.

  The digital camera 10 includes a photographing optical system 11, an image sensor 12, an AFE (Analogue Front End) 13, a DSP (Digital Signal Processor) 14, an operation input unit 15, a liquid crystal monitor 16, a backlight drive circuit 17, and the like.

  The photographing optical system 11 is optically connected to the image sensor 12. An optical image of a subject passing through the photographing optical system 11 is incident on the light receiving surface of the image sensor 12. The image sensor 12 is, for example, a CCD. When the optical image of the subject is received on the light receiving surface, an image signal corresponding to the optical image is generated.

  A diaphragm 18 and a shutter 19 are disposed between the photographing optical system 11 and the image sensor 12. By adjusting the opening of the diaphragm 18, the illuminance of light incident on the light receiving surface of the image sensor 12 is adjusted. Passing and blocking of the subject light beam are switched by opening and closing the shutter 19. Adjustment of the aperture of the diaphragm 18 and opening / closing of the shutter 19 are performed by the optical unit driving unit 20.

  The image sensor 12 is connected to the DSP 14 via the AFE 13. A clock signal is output from the DSP 14 to the AFE 13. The AFE 13 generates a frame signal and an image sensor driving signal based on the clock signal. The image sensor drive signal is transmitted to the image sensor 12. Note that the number of times of imaging per unit time in the image sensor 12 is defined by the frame signal. The image sensor 12 is driven by the image sensor drive signal to generate an image signal synchronized with the frame signal.

  The generated image signal is transmitted to the AFE 13. The image signal is subjected to correlated double sampling, gain adjustment, and A / D conversion in the AFE 13 to be converted into image data. The image data is transmitted to the DSP 14.

  The DSP 14 is connected to a DRAM (Dynamic Random Access Memory) 21 which is a memory for signal processing work. The image data transmitted to the DSP 14 is temporarily stored in the DRAM 21. The DSP 14 performs predetermined signal processing on the image data stored in the DRAM 21.

  A liquid crystal monitor 16 is connected to the DSP 14. The image data that has undergone predetermined signal processing is transmitted to the liquid crystal monitor 16. An image corresponding to the transmitted image data can be displayed on the liquid crystal monitor 16.

  The liquid crystal monitor 16 includes a liquid crystal unit 22 and a backlight 23. Illumination light is irradiated from the backlight 23 to the entire back surface of the liquid crystal unit 22. In the liquid crystal unit 22, the optical image of the subject corresponding to the image data is displayed on the liquid crystal monitor 16 by controlling the transmission and shielding of the illumination light in accordance with the transmitted image data.

  An external card interface 24 is connected to the DSP 14. When a release operation described later is executed, image data that has undergone predetermined signal processing is stored in a card-type memory (not shown) connected to the external card interface 24.

  The DSP 14 is connected to an operation input unit 15 for inputting a command for operating the digital camera 10. The operation input unit 15 includes a release button (not shown), a multi-function cross key (not shown), a power button (not shown), and the like.

  By pressing the power button, the digital camera 10 is turned on / off.

  In addition, the digital camera 10 is provided with a shooting mode for capturing a subject, a playback mode for displaying the captured subject, a setting mode for setting the operation of the digital camera 10, and the like. The operation is executed by performing an input operation on the multifunction cross key.

  In the shooting mode, exposure adjustment and focusing operation are executed by half-pressing the release button. In other words, aperture adjustment, shutter speed adjustment, and gain adjustment in the DSP 14 are performed in exposure adjustment, and a focus lens (not shown) constituting the photographing optical system 11 is moved in focusing operation. When the release button is fully pressed, the shutter 19 is opened / closed, the image is picked up by the image pickup device 12, and the image data is stored in the card type memory.

  When an operator inputs a command for executing a predetermined function as described above to the operation input unit 15, an operation signal corresponding to the command input is transmitted to the DSP 14. In the DSP 14, operation control according to the operation signal is executed.

  For example, when the operation mode of the digital camera 10 is switched to the playback mode, the DSP 14 controls the operation of the card type memory and the liquid crystal monitor 16 so that the image data stored in the card type memory is displayed on the liquid crystal monitor 16. Further, the driving of the image sensor 12 is stopped.

  When the operation mode of the digital camera 10 is switched to the setting mode, the operation of the liquid crystal monitor 16 is controlled by the DSP 14 so that a setting screen is displayed on the liquid crystal monitor 16. The setting screen is stored in a ROM (Read Only Memory: not shown) and is sent as data to the liquid crystal monitor 16 under the control of the DSP 14. Further, similarly to the reproduction mode, the driving of the image sensor 12 is stopped.

  When the operation mode of the digital camera 10 is switched to the photographing mode, the DSP 14 executes the following operation control. First, a through image is displayed on the liquid crystal monitor 16 in the photographing mode. A through image is a real-time image of a subject image received by the image sensor 12. In the shooting mode, when the release button is half-pressed and fully pressed, the exposure adjustment / focusing operation and the still image capturing operation are executed as described above, and the image data is stored in the card-type memory. Control by the DSP 14 in each operation will be described below.

  When switching to the shooting mode, a clock signal having a frequency of 36 MHz is transmitted from the DSP 14 to the AFE 13. When the AFE 13 receives a 36 Mhz clock signal, the AFE 13 generates a frame signal having a frequency of 30 Hz and also generates an image sensor driving signal corresponding to the frequency of the frame signal. Further, the DSP 14 controls the operation of the optical unit driving unit 20 so as to keep the shutter 19 open when switching to the photographing mode.

  The image sensor starts to receive an optical image of the subject based on the image sensor drive signal, and an image signal of one frame is generated. Note that the cycle of the frame signal is the same as the generation cycle of the image signal of one frame, and the image signal is generated every 1/30 seconds.

  The generated image signal is sequentially transmitted to the DSP 14 via the AFE 13. As described above, the DSP 14 performs predetermined signal processing on the transmitted image signal and then transmits it to the liquid crystal monitor 16 as image data. Accordingly, an image updated every 1/30 seconds is displayed on the liquid crystal monitor 16 as a continuous through image.

  The release button is half pressed or fully pressed at a timing desired by the user. When half-pressed, the DSP 14 starts exposure adjustment and focusing operations.

  In exposure adjustment, photometry of the subject is first performed, and exposure adjustment is performed based on the photometry result, such as opening of the aperture 18. Subject photometry is performed by detecting the brightness of the entire image from the image data transmitted from the AFE 13.

  The ROM stores the aperture of the diaphragm 18, the shutter speed, and the gain with respect to the photometric quantity. The opening degree of the diaphragm 18, the shutter speed, and the gain are determined according to the photometric quantity detected by the DSP 14.

  An optical unit driving unit 20 is connected to the DSP 14. The determined aperture and shutter speed of the diaphragm 18 are transmitted as signals to the optical unit drive circuit 20. The optical unit driving unit 20 drives the diaphragm 18 so as to have a predetermined opening, and sets the time until the shutter 19 is closed when the release button is fully pressed.

  In the focusing operation, first, the contrast of the captured image is detected based on the image signal received by the DSP 14. Next, the DSP 14 captures an object and detects contrast while moving the focus lens along the optical axis, and moves the focus lens to a position where the contrast is maximized. A focusing operation is performed by moving the focus lens. The focus lens is moved by the optical unit driving unit 20.

  Next, when the release button is fully pressed, the DSP 14 starts a still image capturing operation. In the still image capturing operation, the DSP 14 causes the AFE 13 to output a frame signal and an image sensor driving signal, and causes the image sensor 12 to capture a subject image. Further, the DSP 14 controls the optical unit driving unit 20 to drive the shutter 19 so as to close when a time set in exposure adjustment has elapsed.

  Further, the image signal generated as described above is subjected to predetermined signal processing in the DSP 14 and stored in the card type memory as image data.

  The above-mentioned digital camera 10 is provided with an energy saving function. By switching the energy saving function from OFF to ON in the setting mode, an energy saving operation described below can be executed.

  The energy saving operation in the present embodiment is performed when the operation mode of the digital camera 10 is the shooting mode.

  The conditions for starting the energy saving operation will be described. A timer 25 is connected to the DSP 14. The DSP 14 causes the timer 25 to start measuring time when a predetermined input operation is performed on the operation input unit 15. The time measured by the timer 25 is detected by the DSP 14.

  The DSP 14 starts the energy saving operation when the measured time passes a predetermined time. By the energy saving operation, the imaging interval for displaying the through image and the illumination light amount of the backlight 23 of the liquid crystal monitor 16 are adjusted.

  Note that the time measured by the timer 25 is reset when a new input operation to the operation input unit 15 is performed. Therefore, the execution of the energy saving operation is started when a new input operation is not performed until a predetermined time has elapsed.

  As described above, a through image is displayed by capturing a subject image usually every 1/30 seconds in the shooting mode. When the time measured by the timer 25 exceeds a predetermined time, an 18 Mhz clock signal having a frequency half the normal frequency is transmitted from the DSP 14 to the AFE 13. When the AFE 13 receives a clock signal having a frequency of 18 Mhz, the AFE 13 generates a frame signal having a frequency of 15 Hz and an image sensor driving signal corresponding to the frame signal having a frequency of 15 Hz. The image sensor drive signal is transmitted to the image sensor 12.

  Accordingly, the image pickup of the subject image by the image pickup device 12 is performed every 1/15 seconds, which is half of the normal value. As the subject is imaged, the image displayed on the liquid crystal monitor is also updated every 1/15 second.

  Further, when displaying a through image in the photographing mode, the backlight drive circuit 17 is controlled by the DSP 14 so that the light emission amount of the backlight 23 becomes the first light emission amount at the normal time. The backlight drive circuit 17 controls the DSP 14 so that the light emission amount of the backlight 23 becomes a second light emission amount lower than the first light emission amount when the time measured by the timer 25 passes a predetermined time. Is done.

  Therefore, when the energy saving operation is started, the through image is displayed darker than usual. Note that the backlight 23 is a light emitting LED, and the amount of light emitted from the backlight 23 is switched by switching the magnitude of the current to flow between the first current value and the second current value smaller than the first current value. It is done.

  In the above-described energy saving operation, when a new input operation to the operation input unit 15 is performed, the time measured by the timer 25 is reset and the time measurement is restarted, and the subject image is captured again every 1/30 seconds. Then, the backlight 23 is driven so that the light emission amount becomes the second light emission amount.

  Next, processing performed by the DSP 14 and the AFE 13 for executing the energy saving operation will be described with reference to the flowchart of FIG. FIG. 2 is a flowchart for explaining a process performed to execute the energy saving operation.

  The process for executing the energy saving operation is started when the photographing mode of the digital camera 10 is activated, that is, when the power of the digital camera 10 is turned on and when the digital camera 10 is switched to the photographing mode. Further, this process is repeated until the power of the digital camera 10 is switched off or switched to another operation mode.

  In step S <b> 100, a 36 Mhz clock signal is transmitted from the DSP 14 to the AFE 13. By receiving a clock signal having a high frequency, an image sensor drive signal corresponding to a high-frequency 30 Hz frame signal is transmitted from the AFE 13 to the image sensor 12. In synchronization with the 30 Hz frame signal, an image signal is generated every 1/30 seconds. Predetermined signal processing is performed on the generated image signal, and the image data is transmitted to the liquid crystal monitor 16.

  In step S101, the backlight 23 is driven so that the light emission amount becomes the first light emission amount. When the light emission amount of the backlight 23 is adjusted, the process proceeds to the next step S102. In step S102, the timer 25 is started to measure time.

  When the time measurement by the timer 25 starts, in step S103, it is determined whether or not a predetermined input operation is input to the operation input unit 15 as a command. When a predetermined input operation is input as a command, the time measured by the timer 25 is reset and the process proceeds to step S104.

  In step S104, an operation corresponding to the input operation input by the command is executed. Thereafter, the process returns to step S102, and the timer 25 is again started to measure time. In step S103, when no command is input, the process proceeds to step S105. In step S105, it is determined whether the time measured by the timer 25 has passed the predetermined time described above and the time is up.

  If the time has not expired, the process returns to step S104, and the processes in steps S102 to S104 are repeated until the time is up. When the time is up, the process proceeds to step S106.

  In step S106, the backlight 23 is driven so that the light emission amount becomes the second light emission amount. When the light emission amount of the backlight 23 is adjusted, the process proceeds to the next step S107.

  In step S107, an 18 Mhz clock signal is transmitted from the DSP 14 to the AFE 13. By receiving a clock signal having a low frequency, an image sensor driving signal corresponding to a low-frequency 15 Hz frame signal is transmitted from the AFE 13 to the image sensor 12. In synchronization with the 15 Hz frame signal, an image signal is generated every 1/15 second. Predetermined signal processing is performed on the generated image signal, and the image data is transmitted to the liquid crystal monitor 16.

  Next, proceeding to step S108, it is determined whether or not a predetermined input operation has been input to the operation input unit 15 as a command. When a predetermined input operation is input as a command, the process returns to step S108, and the process of step S108 is repeated until the command is input. When a command is input, the time measured by the timer 25 is reset and the process proceeds to step S109.

  In step S109, as in step S104, an operation corresponding to the input operation input by the command is executed. After execution of the predetermined operation, the process returns to step S100, and thereafter the same processing is repeated.

  According to the imaging apparatus control unit of the present embodiment having the above-described configuration, when the no-operation state continues, the energy saving operation, that is, the frequency of the frame signal is reduced and the light emission amount of the backlight 23 is reduced. As a result, the power consumption of the entire digital camera 10 can be reduced.

  Further, when a new operation input is performed during the energy saving operation, the frequency of the frame signal and the brightness of the liquid crystal monitor 16 are restored, so that the convenience of the digital camera 10 can be maintained.

  Further, it is possible to stop the execution of the energy saving operation by switching the energy saving function to OFF in the setting mode. Therefore, even when it takes time to select a subject and to determine the timing of imaging by the user, if the execution of the energy saving operation is stopped, the convenience is not impaired.

  In the present embodiment, the time measured by the timer 25 is reset when a new operation input is performed. However, even in a configuration in which the time is not reset, it is possible to reduce power consumption. However, in order to maintain the convenience of the digital camera 10 as described above, it is preferable to reset.

  In the present embodiment, the timer 25 starts measuring after the power of the digital camera 10 is turned on. However, when the camera is switched to the shooting mode, that is, other operations including an operation input for switching to the shooting mode. The configuration may be such that measurement is started only when input is performed.

  Usually, immediately after turning on the power, it is expected that the non-operation state is rarely continued because it is desired to perform imaging of the subject or to perform other operations such as reproduction. Therefore, the power can be reduced without starting the measurement of the timer 25 when the power is turned on.

  In the present embodiment, the liquid crystal monitor 16 is used as the display device, and the light emission amount of the backlight 23 is reduced. However, the light emission amount of the backlight 23 may not be changed. That is, in the case of a reflective liquid crystal display device that does not have a backlight, power consumption can be reduced only by reducing the frequency of the frame signal.

  In the present embodiment, the through image is displayed on the liquid crystal monitor 16, but display means other than the liquid crystal monitor can be applied. If the brightness of the entire image to be displayed can be adjusted, the same effect as in the present embodiment can be obtained.

  In the present embodiment, the image sensor 12 that has received the image sensor drive signal generates an image signal of one frame, but the same effect as in the present embodiment can be obtained even in a configuration that generates an image signal of one field. It is possible to obtain.

  In the present embodiment, the frequency of the frame signal is switched between 30 Hz and 15 Hz, but is not limited to 30 Hz and 15 Hz. When the frequency when executing the energy saving operation is lower than the frequency when executing the normal operation, it is possible to obtain the same effect as the present embodiment.

  In the present embodiment, the energy saving operation is started when the time measured by the timer 25 exceeds a predetermined time. However, the predetermined time may be changed in the setting mode. For example, as shown in FIG. 3, on the energy saving switching time setting screen displayed on the liquid crystal monitor 16, one of a plurality of times may be set as a predetermined time.

1 is a block diagram schematically showing an internal configuration of a digital camera having an imaging device control unit to which an embodiment of the present invention is applied. It is a flowchart for demonstrating the process performed in order to perform an energy saving operation. It is a rear view of the digital camera, and is a diagram showing a state in which an energy saving switching time setting screen is displayed on the liquid crystal monitor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Digital camera 12 Image pick-up element 13 AFE (Analogue Front End)
14 DSP (Digital Signal Processor)
DESCRIPTION OF SYMBOLS 15 Operation input part 16 Liquid crystal monitor 17 Backlight drive circuit 22 Liquid crystal part 23 Backlight 25 Timer

Claims (8)

An image pickup apparatus control unit that controls a predetermined operation set in an image pickup apparatus having an image pickup device for picking up an image of a subject,
A receiving unit that receives a predetermined input operation that is command input as an operation signal in an operation input unit that performs a command input that causes the imaging device to execute a predetermined function;
A timer that starts measuring time when the receiving unit receives the operation signal;
Before the time measured by the timer passes the first time, the imaging device picks up the subject at a first interval, and after the time measured by the timer passes the first time, the image pickup An image pickup apparatus control unit comprising: an image pickup element drive unit that causes the element to pick up an image of the subject at a second interval longer than the first interval.   The imaging apparatus control unit according to claim 1, wherein the elapsed time is reset when the operation signal is newly received by the reception unit. The image sensor driving unit is:
A frame signal generation unit that generates a frame signal that defines the number of times the subject is imaged per unit time in the image sensor;
Before the time measured by the timer passes the first time, the frame signal generation unit generates a frame signal whose cycle is the first interval, and the time measured by the timer is the first time. 3. The imaging apparatus control unit according to claim 1, further comprising: a period adjustment unit that causes the frame signal generation unit to generate a frame signal whose period is the second interval after the elapse of time. .   The imaging device control unit according to any one of claims 1 to 3, wherein the timer starts measuring time even when the power source of the imaging device is turned on.   An image corresponding to the optical image of the subject imaged by the imaging element is displayed darker than the time before the first time after the time measured by the timer has passed the first time. The imaging apparatus control unit according to any one of claims 1 to 4, further comprising a monitor control unit that controls a monitor for displaying an image.   6. The image pickup device drive unit causes the image pickup device to continue image pickup at the first interval in response to a switch stop command input to the operation input unit. The imaging device control unit according to Item.   In response to the switching stop command input to the operation input unit, the image sensor driving unit causes the image sensor to continue imaging at the first interval, and the monitor control unit sets the average luminance of the entire monitor to the first luminance. The imaging apparatus control unit according to claim 1, wherein the monitor is driven so as to be maintained as it is. An image sensor for imaging a subject;
An operation input unit for inputting a command to execute a predetermined function;
A timer that starts measuring time when a predetermined input operation is performed on the operation input unit;
Before the time measured by the timer passes the first time, the imaging device picks up the subject at a first interval, and after the time measured by the timer passes the first time, the image pickup A digital camera comprising: an image pickup device driving unit that causes the device to pick up an image of the subject at a second interval longer than the first interval.

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